Internal combustion engines may utilize direct fuel injection, wherein a precisely controlled amount of fuel is injected under high pressure into each engine cylinder, thereby increasing fuel efficiency and power output of the engine. In traditional direct fuel injectors, the injector nozzle hole configuration and geometry can regulate combustion characteristics and affect vehicle emissions. The fuel is typically injected from a sac at the tip of the fuel injector needle into the engine cylinder through a plurality of holes, configured in various forms to increase atomization and improve air-fuel mixing.
However, the inventors herein have recognized that in a combustion chamber of an engine, air flow may be asymmetrical due to the positioning of intake and exhaust valves along the combustion chamber. The opening of the intake valve during an intake stroke of the engine may generate turbulent air flow having high swirl and tumble in some parts of the combustion chamber, while less swirling, tumbling, and turbulence may be seen in other locations of the combustion chamber. Hence, if fuel is delivered uniformly (e.g., if the same volume of fuel is delivered) in all parts of the combustion chamber, fuel wall penetration may increase and fuel spray atomization may decrease in certain parts of the combustion chamber, such as the regions of the combustion chamber that experience less turbulent air flow, which may eventually degrade emissions.
In one example, the issues described above may be addressed by a fuel injector system including an injector body with a plurality of nozzle holes, and an injector needle coupled to an injector pin, the injector pin including a curved fuel channel in fluidic communication with a fuel reservoir inside the injector pin, the injector needle and the injector pin housed inside the injector body, the curved fuel channel including a first region having a first width and a second region having a second width, larger than the first width, and when the injector needle is actuated, the first region is configured to be in fluidic communication with a first nozzle hole of the plurality of nozzle holes to deliver a first fuel volume, and the second region is configured to be in fluidic communication with a second nozzle hole of the plurality of nozzle holes to deliver a second fuel volume, larger than the first fuel volume.
One example method of operating the above described fuel injector may include actuating a needle having a curved fuel channel housed within a fuel injector body to sequentially move the needle downward from a closed position through a plurality of open positions, fluidically connecting a width of the curved fuel channel to a specific nozzle hole/s, injecting a desired volume of fuel into different areas of a combustion chamber. In one example, a first width of the fuel channel may fluidically connect to a first nozzle hole, followed by moving the needle downward, fluidically uncoupling the first width of the fuel channel from the first nozzle hole, and fluidically connecting a second width of the fuel channel to a second nozzle hole at a second open position of the plurality of open positions, where the second width is greater than the first width. A first fuel volume may be injected through the first nozzle hole to an area of low tumble and swirl in a combustion chamber, and a second fuel volume may injected through the second nozzle hole to an area of high tumble and swirl in the combustion chamber, where the first fuel volume may be less than the second fuel volume.
In this way, in a multi-hole fuel injector assembly, an injector needle with a curved fuel channel of non-uniform width may be sequentially positioned, such that each position may establish fluidic communication between the curved fuel channel and specific nozzle hole/s for a duration based on the width of the curved fuel channel in apposition with the specific nozzle hole/s. At each position, a specific volume of fuel may be injected through the nozzle hole into a specific area of the combustion chamber, thereby minimizing fuel spray interaction and increasing fuel spray atomization.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.